CO2 compressor

ABSTRACT

A CO 2  compressor for an air conditioner of a motor vehicle is suggested having a sealing device, assigned to the driveshaft of the CO 2  compressor, which is implemented as a sliding ring. The CO 2  compressor features a lubrication device, in which the sealing device is supplied a lubricant flow effected by centrifugal forces.

The present invention relates to a CO₂ compressor for an air conditionerof a motor vehicle having a sliding ring seal.

CO₂ compressors of the type referred to here are known. It isdisadvantageous that high wear frequently appears in the sliding rigseal comprising a sliding ring and a counter ring, which particularlyoccurs because the sliding ring, which has a spring force applied to it,and the counter ring must be pressed against one another with arelatively high force in order that sufficient pressure is produced inthe region of the sealing surface lying between the counter ring and thesliding ring and escape of CO₂ may be prevented. As a rule, in a slidingring seal, the counter ring is implemented as fixed while the slidingring rotates with the driveshaft of the compressor and has a springforce applied to it. However, embodiments are also known in which thesliding ring is fixed and the counter ring rotates.

The object of the present invention is to provide a CO₂ compressor whichis distinguished by reduced wear.

To achieve this object, a CO₂ compressor is suggested which ischaracterized in that a lubrication device is provided which generates alubricant flow. This is produced by centrifugal forces. It is thereforepossible in a simple way to ensure lubrication in the region of thesliding ring seal. Costly devices for generating the lubricant flow mayparticularly be dispensed with.

An exemplary embodiment of the CO₂ compressor is preferred which isdistinguished by a component, rotating during operation of the CO₂compressor and acting as a centrifugal force pump, which works togetherwith the lubricant in such a way that through the rotation of thecomponent, given during operation of the CO₂ compressor, the lubricantis swirled so that centrifugal forces build up a flow which flowsoutward from the rotational axis of the flange.

During rotation of the component the lubricant is thus displaced outwardby the centrifugal forces and swirls and therefore reaches the innerside of the CO₂ compressor and/or its housing, so that a liquid ring isbuilt up which displays a slight overpressure dependent on therotational speed of the component and the quantity of liquid. Thisoverpressure in the liquid ring causes an oil-CO₂ mixture to be movedfrom the outside into the inside of the CO₂ compressor via suitableopenings, so that a lubricant flow arises which is guided to the slidingring seal. It is clear that a CO₂ compressor of this type has a simpledesign and is distinguished by effective lubricant flow. This flow mayalso be guided in such a way that bearing devices of the CO₂ compressorare also supplied.

Furthermore, an exemplary embodiment of the CO₂ compressor is preferredwhich is distinguished in that the rotatable component is a flangeprovided inside the CO₂ compressor. This flange is used, for example, todrive a compressor unit of the CO₂ compressor and is therefore referredto as a driver flange. The compressor unit may be implemented in atypical way, for example as an axial piston pump. The flange is locatedinside the CO₂ compressor and works together, as described above, withthe lubricant so that, through the rotation of the flange given by theoperation of the CO₂ compressor, a flow acting outward from therotational axis of the flange is built up by centrifugal forces, withswirls caused by the flange also acting on the lubricant, whichadditionally contribute to the flow. During rotation of the flange, theliquid ring described is thus built up, which finally causes thelubricant flow.

In addition, an exemplary of the CO₂ compressor is preferred which isdistinguished in that the sliding ring seal has a driver device whichgrips the sliding ring rotating with the driveshaft and sets it inrotation. In spite of the high pressures which are necessary in a CO₂compressor, synchronous rotation of the sliding ring with the driveshaftis thus ensured, with no wear arising in the region between thedriveshaft and the sliding ring because of this.

An exemplary embodiment of the CO₂ compressor is preferred in which thedriver device is coupled with the flange driven by the driveshaft of theCO₂ compressor so that they rotate together.

Furthermore, an exemplary embodiment of the CO₂ compressor is preferredin which the driver device includes a spring device which applies aprestressing force to one tongue of the driver device. A design of thistype greatly simplifies the assembly of the sliding ring seal, since thetongue of the driver device catches quasi-automatically, or at latestafter one rotation of the driver device. For example, the tongue mayengage in a flange which is set in rotation by the driveshaft.

In addition, an exemplary embodiment of the CO₂ compressor is preferredin which the driver device has at least one driver arm which workstogether with the sliding ring.

In addition, an exemplary embodiment of the CO₂ compressor is preferredin which the driver device is producible from a flat material, forexample from sheet metal.

Furthermore, an exemplary embodiment of a CO₂ compressor is preferred inwhich the driver device is producible in a stamping-bending method, andtherefore in a simple, economical way.

In a further preferred exemplary embodiment of the CO₂ compressor, thedriver device is produced from one piece.

A further preferred exemplary embodiment of the CO₂ compressor ischaracterized in that the sliding ring seal has a fixed counter ring inwhich is coupled with a housing part of the CO₂ compressor and acoupling device which effects the coupling. In this way, a rigidcoupling may be implemented between the housing and the counter ring, sothat frictional forces between the housing and the counter ring areprevented.

In addition, an exemplary embodiment of the CO₂ compressor is preferredwhich is distinguished in that the coupling device has a dihedron and/orat least one coupling pin.

Furthermore, an exemplary embodiment of the CO₂ compressor is preferredwhich is distinguished in that the sliding ring seal has a sleeveimplemented as a housing, which allows the sliding ring seal to beintegrated as a completely assembled device in the CO₂ compressor.

In addition, an exemplary embodiment of the CO₂ compressor is preferredin which a bearing device assigned to the driveshaft is provided, andthe bearing device has a bearing positioned outside the CO₂ atmospherewhich is thus removed from the damaging influences of this medium.

In addition, an exemplary embodiment of the CO₂ compressor is preferredwhich is characterized in that the bearing is sealed and lubricated withgrease. The sealing provides additional protection of the bearing andkeeps the lubricant from being affected by the CO₂.

Furthermore, an exemplary embodiment of the CO₂ compressor is preferredin which a relief chamber is provided between the bearing device and thesealing device. This is used for decoupling the bearing from the CO₂atmosphere.

Finally, an exemplary embodiment of the CO₂ compressor is preferred inwhich the relief chamber has a relief channel. This preferably producesa connection between the relief chamber and the atmosphere, so that CO₂which penetrates the relief chamber may escape without anything furtherand pressure build-up is avoided.

The invention is described more detail in the following with referenceto the drawing.

FIG. 1 shows a part of a CO₂ compressor in longitudinal section;

FIG. 1 a shows a detail from FIG. 1;

FIG. 2 shows a perspective view of a counter ring of a sliding ringseal;

FIG. 3 shows a perspective view of a sliding ring of a sliding ringseal, and

FIG. 4 shows a perspective view of a driver device.

The illustration in FIG. 1 shows a part of a CO₂ compressor 1 inlongitudinal section which is used for an air conditioner of a motorvehicle and includes a driveshaft 3. This is set in rotation in atypical way, for example via a belt pulley of the internal combustionengine of the motor vehicle. Only a section of the driveshaft is shownhere. The belt pulley is set on the left end of a driveshaft 3, notshown here, and is connected in a known way with the driveshaft so thatthey rotate together. The driveshaft extends into a housing 5 of CO₂compressor 1 and drives a conveyor device, which may, for example, beimplemented as an axial piston machine, housed in a drive chamber 9, viaa flange 7, with which it is connected so that they rotate together.Specifics of the conveyor device are not reproduced here. They are knownto those skilled in the art.

During operation of CO₂ compressor 1, CO₂ is located in drive chamber 9under a high overpressure. This overpressure acts via borings 11 a and11 b, which penetrate flange 7, up to a sealing device 13, which sealsdrive chamber 9 tightly in relation to the surroundings.

Sealing device 13 has a sliding ring seal, which in this case comprisessliding ring 19, which rotates with driveshaft 3 and has springresistance applied to it, and a fixed counter ring 21, coupled with ahousing part of CO₂ compressor 1, as well as a coupling device effectingthe coupling between counter ring 21 and the housing part.

Sealing device 13 is assigned a lubrication device 15, which generates alubricant flow indicated by arrows 17 a to 17 e.

Sealing device 13 is implemented as a sliding ring seal which includessliding ring 19, which may be set in motion synchronously withdriveshaft 3, and a counter ring 21 fixed with housing 5. Sliding ring19 and counter ring 21 are pressed against one another by a springassembly 23. They are in contact with one another in the region of asliding surface 25 used as a sealing surface, to which rotational axis27 of the driveshaft is perpendicular. Sliding surface 25 is a ringsurface which runs concentrically around driveshaft 3. This slidingsurface finally seals drive chamber 9 in relation to the surroundings.It is necessary to press sliding ring 19 with a high force againstcounter ring 21, because the CO₂ molecules are relatively small andtherefore may easily overcome sealing surfaces at the high pressurelevels occurring during operation of CO₂ compressor 1.

Sliding ring 19 is sealed relative to the lateral surface of thedriveshaft by means of a suitable seal, in this case by means of anO-ring 29.

In the exemplary embodiment illustrated here, sealing device 13 includesa sleeve 31, also referred to as a cartridge, which surrounds slidingring 19 and counter ring 21 and which is connected with counter ring 21so that they rotate together. Counter ring 21 is sealed via a suitableseal, in this case via a second O-ring 33, relative to sleeve 31, whichin turn is sealed via a third O-ring 35 relative to housing 5.

Overall, it thus results that drive chamber 9 is sealed in relation todriveshaft 3 via a first O-ring 29 and in relation to the atmosphere viasliding surface 25, which acts as a sealing surface, second O-ring 33,and third O-ring 35.

Lubrication device 15 is implemented in such a way that CO₂ with oilflows out of drive chamber 9 onto sliding ring 19 and counter ring 21and at the same time lubricates sliding surface 25.

Flange 7 supports itself in this case on housing 5 via a first bearingdevice 37, which, for example, comprises a roller bearing 39. Flange 7may thus rotate relative to housing 5.

First bearing device 37 lies in the region of the lubricant flow comingout of drive chamber 9.

The lubricant flow will be described in more detail with reference toFIG. 1.

The starting point for the lubricant flow caused by centrifugal forcesis a component which may be set in rotation during operation of CO₂compressor 1. In the exemplary embodiment shown in FIG. 1, this isflange 7. This delimits drive chamber 9, in which a suitable compressorunit, for example an axial piston pump, is housed and which is drivenvia flange 7, which is therefore also referred to as a driver flange.Flange 7 works together with the lubricant present in drive chamber 9,for example an oil, which is centrifuged outward together with the CO₂present in drive chamber 9 during a rotation of flange 7 and forms aliquid quasi-ring on the inner surface which surrounds drive chamber 9.Through the centrifugal forces, the lubricant is centrifuged outward insuch a way that an overpressure is built up in the liquid ring. This hasthe effect that the lubricant—possibly together with the CO₂—is guidedto sealing device 13.

The lubrication device shown in FIG. 1, which thus comprises therotating component and/or in this case flange 7, via which the liquidring is built up, includes at least one channel running from the liquidring in the direction toward rotational axis 27, for example a boring12, via which the medium standing under an overpressure is pressed outof the liquid ring in the direction toward sealing device 13. Thelubricant flow running into boring 12 is indicated by an arrow 16.

The medium flowing inward inside boring 12 may form two partial flowswhich are indicated by arrows 17 a and 17 b. The lubricant flow reachessleeve 31 in its further course. One partial flow runs into the insideof the sleeve, which is indicated by arrows 17 c, 17 d, and 17 e. Thispartial flow leads past counter ring 21 and sliding ring 19, withsliding surface 25 particularly being lubricated. Sliding ring 19 andcounter ring 21 surround driveshaft 3, as does sleeve 31. The lubricantflow also runs in a ring shape around sliding ring 19 and counter ring21, so that sealing surface 25 is completely lubricated and also cooled.

The lubricant flow running into the inside of sleeve 31 enters drivechamber 9 through borings 11 a and 11 b. In this way the loop is closed:the lubricant which has reached this point may now be in turn becentrifuged outward by the rotating component, in this case via flange7, and reach the liquid ring which presses the lubricant under anoverpressure through sleeve 31.

Sleeve 31 presses tightly against flange 7, which rotates relative tosleeve 31. Borings 11 a and 11 b are positioned at a distance torotational axis 27 such that they form a fluid connection between sleeve31, which acts as a housing for the sliding ring seal, and drive chamber9, and guarantee that a closed lubricant flow arises and a reliablelubrication of sliding surface 25 acting as a seal is ensured.

It may be seen in FIG. 1 that an inlet 41 is provided in sleeve 31 at adistance to flange 7 measured in the axial direction, via which theCO₂-oil mixture may enter the inside of sleeve 31. The lubricant flow isguided in such a way that it directly meets sliding surface 25 to belubricated, as indicated by arrow 17 c, and at the same time runsessentially radially from the outside to the inside in the directiontoward rotational axis 27. A deflection then occurs so that thelubricant flow runs more or less parallel to central axis 27 throughsleeve 31, which arrow 17 e shows. It then exits, as mentioned, viaborings 11 a, 11 b into drive chamber 9. With the course of thelubricant flow selected here, which flows along the sliding ring seal,cooling of sealing device 13 may also be ensured.

In the exemplary embodiment shown in FIG. 1, the lubricant flow finallyruns, corresponding to arrow 17 b, inside boring 12 up to slidingsurface 25. Inside boring 12, the flow runs approximately perpendicularto rotational axis 27. It then adjoins a flow region which is indicatedby arrow 17 b. The lubricant flow runs here from first bearing device 37to inlet 41 of sleeve 31 at an angle which is approximately 45° in thiscase. In FIG. 1, a gap 43 is shown which is implemented between housing5 and flange 7 and within which a part of the lubricant flow may run.This is indicated by arrow 17 a. The flow shown here runs essentiallyradially inward in the direction toward rotational axis 27. Gap 43 has afluid connection with a ring gap 45 surrounding sleeve 31, in which thepartial flow given in gap 43 continues and runs outward around sleeve 31until it also reaches inlet 41. This partial flow is not absolutelynecessary. However, it does contribute to the additional cooling ofsleeve 31.

It is indicated by an arrow P that the lubricant flow goes outward froma region radially outside bearing device 37, specifically from theliquid ring described above, and then runs inward to sealing device 13.Finally, the lubricant flow enters drive chamber 9 via borings 11 a, 11b through flange 7, which is indicated by arrow P′.

It is obvious without anything further that for the basic principle ofthe lubricant flow illustrated here, the number of borings 12 is not ofdirect significance. In order to ensure a uniform flow, approximatelyfour borings are preferably provided, through which the lubricant maypass from the liquid ring inward to sealing device 13.

FIG. 1 shows that in the exemplary embodiment shown here, driveshaft 3is supported relative to housing 5 via a second bearing device 47. Thisis positioned at an interval to sealing device 13 outside the CO₂atmosphere, so that in this case an intermediate relief chamber 49 isformed which separates second bearing device 47 and the sealing device.Relief chamber 49 is used so that CO₂ and/or CO₂-oil mixture emittedfrom sealing device 13 does not directly meet second bearing device 47,particularly not under high pressure, and affect it. Grease lubricationprovided in second bearing device 47 has an elevated service life inthis way. This may be increased even more if the relief chamber isconnected via a relief channel 51, which penetrates housing 5, with aregion standing under a lower pressure, particularly the surroundings,in this case with the atmosphere, so that a pressure build-up in reliefchamber 49 which is too great is reliably avoided. The service life ofsecond bearing device 47 may also be increased if it is sealed.

Second bearing device 47 may be positioned near the belt pulley, notshown here, which is connected with driveshaft 3 so that they rotatetogether, and is preferably placed directly under the belt pulley. Inthis way, a very small bend of the shaft and/or bend of driveshaft 3results, so that stress of the shaft seal and/or sealing device 13 isreduced to a minimum. It is particularly avoided that counter ring 21and sliding ring 19 are tilted relative to one another in the region ofsliding surface 25 serving as a sealing surface, which would cause highfrictional forces and occurrences of wear.

It is obvious without anything further that a floating mount ofdriveshaft 3 may be implemented with second bearing device 47, which isindicated here only by a technical symbol, in which all bearing devicesof the driveshaft are positioned on one side of housing 5, namely on theside of the belt pulley.

It was already explained above that the sliding ring seal of sealingdevice 13, which includes sliding ring 19 and counter ring 21, is toprevent the passage of CO₂ in the region of sliding surface 25.Therefore, sliding ring 19 and counter ring 21 are pressed against oneanother with high forces, spring assembly 23 serving for elasticpressures in this case. Due to the high forces acting in sliding surface25, counter ring 21 must be prevented from racing relative to sleeve 31and/or housing 5 and/or sliding ring 19 from racing relative todriveshaft 3. O-rings 29, 33, and 35 mentioned are not sufficient in allcases to apply the necessary forces. Therefore, it is advantageous toprovide a positive fit between the driveshaft on one hand and/or thefixed housing on the other hand and thus to implement a coupling device.

In FIG. 1, a driver device 53 assigned to the coupling device isprovided, which couples sliding ring 19 with driveshaft 3 so that theyrotate together. In the exemplary embodiment shown here, the coupling isnot provided directly with driveshaft 3 itself, but with flange 7coupled rigidly with driveshaft 3. For this purpose, driver device 53has at least one, preferably two, tongues 55 a and 55 b, of which onlytongue 55 a is visible here. These engage in a suitable depressionprovided on flange 7, in this case in one of the borings, specificallyin boring 11 b, which penetrates flange 7. In this way, driver device 53is coupled with driveshaft 3 via flange 7 so that they rotate together.The rotational movement is transferred to sliding ring 19 via at leastone, preferably two, driver arms 57 a, 57 b, of which a first driver arm57 a is shown here. This engages in a depression in sliding ring 19,which is implemented here as groove 59.

It is already clear from the illustration shown in FIG. 1 that driverdevice 53 is producible from a flat material which is elastic per se,preferably from a metal sheet. During the assembly of CO₂ compressor 1,particularly during the coupling of driveshaft 3 with flange 7, driverdevice 53 may come into contact at any desired point with flange 7,since tongue 55 a may be pressed back from the positioned shown in FIG.1 to the left, i.e., in the direction toward sealing device 13. Ifdriveshaft 3 is now rotated relative to flange 7, tongue 55 a finallyengages in boring 11 b and snaps into it, so that it assumes theposition illustrated in FIG. 1.

In order to ease the snapping of tongue 55 a of driver device 53 intoboring 11 b, the outer contour of tongue 55 a may preferably be shapedas rounded and/or U-shaped. This is visible in the detail illustrationin FIG. 1 a, which shows tongue 55 a illustrated in FIG. 1 in a lateralview, which corresponds to a bottom view of FIG. 1. It is essential thattongue 55 a is also otherwise implemented so that it does not pop out ofboring 11 b unintendedly during transmission of a torque.

The spring effect and/or prestressing force which acts on tongue 55 a isprovided on one hand by the intrinsic elasticity of driver device 53,but, on the other hand, also by the spring system, implemented here as aspring assembly 23, which is also used for the purpose of pressingsliding ring 19 against counter ring 21, which supports itself on sleeve31, which in turn presses against a suitable shoulder 61 inside housing5. The sliding ring seal is thus elastically clamped by springs betweenshoulder 61 and flange 7.

To complete the coupling device, counter ring 21 is positionednon-rotatable relative to housing 5. The non-rotatable fixing of counterring 21 on housing 5 may, as described in more detail below, beperformed, on one hand, by a non-rotatable attachment to sleeve 31,which is fixed in housing 5, or, on the other hand, directly to housing5 itself.

FIG. 2 shows a preferred embodiment of the non-rotatable couplingbetween counter ring 21 and sleeve 31. FIG. 2 shows a perspective viewof the left side—in FIG. 1—of counter ring 21, i.e., the side which liesopposite sliding surface 25.

In the exemplary embodiment illustrated here, counter ring 21 isprovided with a dihedron 63 assigned to the coupling device, whoseextent—measured in horizontal direction—is less than the diameter ofcounter ring 21. The dihedron is flattened on its upper and lower sides.The dihedron projects relative to face 65 of counter ring 21 and engagesin an appropriately shaped depression in sleeve 31, which is anchorednon-rotatably in a suitable, known way in housing 5.

FIG. 2 merely shows a schematic diagram from which the design of counterring 21 is visible. Therefore, the dimensions do not correspond withthose of FIG. 1.

Counter ring 21 has a central opening 67, through which driveshaft 3passes. The dimensions of opening 67 are selected so that driveshaft 3,not shown here, is rotatable within counter ring 21. In FIG. 2, secondO-ring 33 is also indicated.

FIG. 3 shows the second ring of the sliding ring seal, specificallysliding ring 19, which also has a central opening 69 which is penetratedby driveshaft 3, which, however, is not shown here.

Sliding ring 19 shown here is provided on its outer side with tworecesses, implemented here as grooves 59 a and 59 b, in which driverarms 57 a and 57 b of driver device 53 engage, which were explained withreference to FIG. 1.

Face 71 of sliding ring 19, on the left in FIG. 3, forms the slidingsurface 25, used as the sealing surface with face 73, on the right inFIG. 2, of counter ring 21, which was described in more detail withreference to FIG. 1.

Right face 75 of sliding ring 19 engages with spring assembly 23described with reference to FIG. 1; it faces flange 7, which wasdescribed with reference to FIG. 1. In addition, it points in thedirection of driver device 53, as was described in more detail withreference to FIG. 1 and which is shown in perspective in FIG. 4. O-ring23, mentioned in the explanations for FIG. 1, is not shown here.

Driver device 53 illustrated in FIG. 4 has a main body 77, from which,on one hand, tongues 55 a and 55 b, described with reference to FIG. 1,project, and, on the other hand, driver arms 57 a and 57 b project. Mainbody 77 has a central opening 79, through which driveshaft 3 passes, sothat it may be positively connected with flange 7 and a torque istransferable from driveshaft 3 to flange 7.

It is obvious from the perspective view shown in FIG. 4 that driver arms57 a, 57 b are bent by approximately 90° relative to main body 77, inorder to engage in grooves 59 a, 59 b of adjoining sliding ring 19. Onthe opposite side of main body 77, tongues 55 a, 55 b are located, whichare to engage in borings 11 a, 11 b in flange 7.

It may be seen unequivocally in FIG. 4 that driver device 53 isimplemented in one piece and is producible from a flat material. In thiscase, any sufficiently strong material which is also as elastic aspossible may be used. Preferably, a metal sheet is used (steel ortitanium or the like), which may be formed easily in a stamping-bendingmethod and/or deep drawing method, so that the production costs arerelatively low.

It is essential for the main function of driver device 53 that, on onehand, it is engaged with the driveshaft, and/or in this case with flange7 set in rotation by driveshaft 3, so that they rotate together and, onthe other hand, it is coupled with sliding ring 19 so that they rotatetogether. It is clear that in this case the number of driver arms 57 a,57 b and/or tongues 55 a, 55 b, is not important, nor is theirarrangement. In the exemplary embodiment of driver device 53 illustratedin FIG. 4, each two driver arms 57 a, 57 b and tongues 55 a, 55 b arepositioned lying opposite one another. At the same time, they arepositioned on an imaginary diameter line. The diameter lines intersecthere at an angle of 90°. In the sectional illustration in FIG. 1, it ispresumed only for exemplary purposes that a tongue 11 b is alsopositioned lying opposite a driver arm 57 a. An embodiment of this typeis, however, also usable without anything further. In this case, tongue55 b would then be positioned opposite driver arm 57 b. For the basicfunction of driver device 53, as mentioned, the arrangement of thedriver arms and tongues does not play any significant role.

However, it is decisive that main body 77 of driver device 53 isimplemented as elastic per se and therefore exercises a specificprestressing force on tongues 55 a, 55 b. This may, however, also oradditionally be applied by spring assembly 23, so that tongues 55 a and55 b have a prestressing force acting in the direction of flange 7applied to them. Through this prestressing force it is ensured thatduring assembly, care does not initially have to be taken in thepositioning of driver device 53 relative to flange 7 and/or borings 11a, 11 b. After flange 7 is placed on the face of driveshaft 3, tongues55 a, 55 b, which were initially pressed back by the left side of flange7, finally catch in borings 11 a, 11 b and thus produce the couplingbetween flange 7 and the driver device and/or sliding ring 19 so thatthey rotate together. In this way, assembly is significantly simplified.

Finally, it is clear that the two rings of the sliding ring seal arecoupled by means of the coupling device with, on one hand, housing 5 orwith, on the other hand, driveshaft 3, respectively, so that they rotatetogether, counter ring 21 being coupled via dihedron 63 and via sleeve31 with housing 5 and sliding ring 19 being connected via driver device53 with flange 7, which is coupled with driveshaft 3 so that they rotatetogether, so that slipping is prevented. During relative rotation ofdriveshaft 3 in relation to housing 5, displacement of the rings of thesliding ring seal relative to housing 5 or relative to driveshaft 3,respectively, is prevented, so that associated O-rings 23, 33, and 35are therefore not subject to wear. Relative rotation occurs exclusivelyin the region of sliding surface 25, which is protected by the lubricantflow against too great a wear. Furthermore, second bearing device 47ensures that sliding surface 25 is essentially perpendicular onrotational axis 27 and right face 73 of counter ring 21 runs parallel toleft face 71 of sliding ring 19. In this way, on one hand, an optimalseal of drive chamber 9 or the lubricant flow, respectively, relative tothe surroundings or relief chamber 49, respectively, is guaranteed, and,on the other hand, the wear is reduced to a minimum.

All of the exemplary embodiments shown in FIGS. 1 to 4 share the featurethat the lubricant flow runs inward, viewed outward from the slidingsurface 25, and is generated by a rotating component, in this caseflange 7, acting as a centrifugal force pump. This centrifuges theCO₂-lubricant mixture present in drive chamber 9 outward due tocentrifugal forces and possibly also due to swirls in such a way that aliquid ring is built up, within which an overpressure is built up. Thisdepends on, among other things, the speed of the component and itsdesign, as well as on the temperature and viscosity of the lubricant.The overpressure may be, for example, 3 mbar to approximately 200 mbar,preferably

10 mbar to 50 mbar.

The lubricant flow is used, on one hand, for the purpose of ensuringlubrication in the region of sliding surface 25, and, on the other hand,for the purpose of cooling this region of sealing device 13 and/or thesliding ring seal. In this case, it may be established that withincreasing speed of CO₂ compressor 1, on one hand, the heat build-up inthe region of sliding surface 25 increases, but, on the other hand, thestrength of the lubricant flow and therefore the cooling also increase.

An essential advantage of CO₂ compressor 1 illustrated here is that thelubricant flow is generated by centrifugal force and swirls of theflange and is guided back into the drive chamber center having “lower”pressure through suitable borings 12, 15, 43, 45, 11 a, and not, as inknown devices, solely by gravity. In the known devices, it was ofdecisive significance to bring the CO₂ compressor into a specificassembly position, in order to ensure a sufficient lubrication andcooling. In CO₂ compressor 1 described here, it is possible to positionit in any desired assembly position, since the lubricant flow, andtherefore also the lubrication and cooling, may be ensured in any case.

1. A CO₂ compressor for an air conditioner of a motor vehicle having asealing device, assigned to a driveshaft of the CO₂ compressor, which isimplemented as a sliding ring, comprising: a lubrication devicestructured to supply the sealing device with a lubricant flow effectedby centrifugal forces, the sealing device including a sleeve enclosing abearing seal ring having the sliding ring which rotates with thedriveshaft and a driver device engaged with the sliding ring as part ofa coupling device to couple the sliding ring with the driveshaft forrotation with the drvieshaft, the driver device comprising at least oneaxially-extending driver arm which engages in a depression formed in thesliding ring and at least one axially-extending tongue and a springdevice which applies a prestressing force to the at least one tongue ofthe driver device, the lubrication device comprising a ring gap formedabout said sleeve and being in fluid communication with the bearing ringseal and sliding ring via a sleeve inlet.
 2. The CO₂ compressoraccording to claim 1, wherein a component acting together with thelubricant, which is rotatable during operation of the CO₂ compressor,forms a centrifugal force pump to generate the lubricant flow.
 3. TheCO₂ compressor according to claim 2, wherein the component is a flangeprovided inside the CO₂ compressor.
 4. The CO₂ compressor according toclaim 1, wherein the driver device is coupled with a component driven bythe driveshaft of the CO₂ compressor so that said driver device andcomponent driven by the driveshaft rotate together.
 5. The CO₂compressor according to claim 4, wherein the driver device is coupled toa flange so that the flange and the driver device rotate together. 6.The CO₂ compressor according to claim 5, wherein the driver device isformed from a single piece of material.
 7. The CO₂ compressor accordingto claim 1, wherein the driver device is formed from a flat material. 8.The CO₂ compressor according to claim 7, wherein the driver device isformed from sheet metal.
 9. A method for forming a CO₂ compressor as setforth in claim 1, the method comprising forming the driver device in astamping-bending method.
 10. The method according to claim 9, whereinthe driver device is formed by a deep drawing method.
 11. The CO₂compressor according to claim 1, wherein the driver device is formedfrom a single piece of material.
 12. The CO₂ compressor according toclaim 1, wherein the CO₂ compressor has a housing and wherein thesealing device has a fixed counter ring coupled to part of the housingof the CO₂ compressor and a coupling device effecting the coupling. 13.The CO₂ compressor according to claim 12, wherein the coupling deviceincludes a dihedron.
 14. The CO₂ compressor according to claim 1,further comprising a second bearing device, assigned to the driveshaft,which has a bearing positioned outside the CO₂ atmosphere.
 15. The CO₂compressor according to claim 14, wherein the bearing of said secondbearing device is sealed and/or lubricated with grease.
 16. The CO₂compressor according to claim 14, further comprising a relief chamberdisposed between the second bearing device and the sealing device. 17.The CO₂ compressor according to claim 16, wherein the relief chamber hasa relief channel which produces a connection between the relief chamberand the atmosphere.
 18. The CO₂ compressor of claim 1 wherein thelubrication device further comprises a radially-extending gap positionedperpendicular to the sealing device to direct lubricant to the bearingseal ring and sliding ring.
 19. The CO₂ compressor of claim 18 furthercomprising a flange rotatably driven by the driver device, and whereinthe radially-extending gap is positioned between the flange and a casingof the compressor.
 20. The CO₂ compressor of claim 1 wherein thelubrication device further comprises a bore formed through a casing ofthe compressor, said bore being positioned at a 45° angle to the sleeve.21. The CO₂ compressor of claim 20 further comprising aradially-extending gap positioned perpendicular to the sleeve to directlubricant to the bearing seal ring and sliding ring under centrifugalforce.
 22. A CO₂ compressor for an air conditioner of a motor vehiclecomprising: a driveshaft; a sealing device disposed about the driveshaftso as to form a sliding ring, the sealing device comprising; a sleevedisposed about said sliding ring; a lubrication device providing a ringgap disposed about said sleeve and being in fluid communication withsaid sliding ring to provide a lubricant flow to said sliding ringeffected by centrifugal forces, said ring gap further providing acooling effect to said sleeve; a bearing seal ring having the slidingring which rotates with the driveshaft; and a driver device engaged withthe sliding ring as part of a coupling device to couple the sliding ringto the driveshaft for rotation with the driveshaft, the driver devicecomprising at least one axially-extending driver arm which engages adepression in the sliding ring and at least one axially-extending tonguesubject to a prestressing force.
 23. The CO₂ compressor according toclaim 22 further comprising a spring device for applying theprestressing force to the at least one tongue of the driver device. 24.The CO₂ compressor according to claim 22, further comprising a flangewhich acts together with a lubricant supplied by the lubrication device,the lubrication device being rotatable during operation of the CO₂compressor to form a centrifugal force pump to generate the lubricantflow.
 25. The CO₂ compressor according to claim 22, wherein the driverdevice is coupled with a component driven by the driveshaft of the CO₂compressor so that the component and driver device rotate together. 26.A method for forming a CO₂ compressor having a driveshaft, and a sealingdevice, the method comprising: selecting the sealing device having arotatable sliding ring and a driver device with at least oneaxially-extending tongue subject to a prestressing force provided bydisposing a spring in the sealing device between the sliding ring anddriver device to apply the prestressing force to the at least onetongue, said driver device having at least one drive armaxially-extending in a direction away from said at least oneaxially-extending tongue and engaged with a depression formed in saidrotatable sliding ring to impart rotation to said rotatable slidingring; providing a housing for said sealing device; and providing alubrication device having a ring gap positioned about a sleeve that isdisposed about said rotatable sliding ring, the ring gap supplyinglubricant to the rotatable sliding ring and forming a lubricant flow bycentrifugal force.
 27. The method according to claim 26, furthercomprising disposing said sliding ring so that the sliding ring rotateswith the driveshaft.